Declare function from within dictionary

Question

def mainProgram(myDict):
    methodDict = {'add': addDB(myDict, params[1], params[2]),
                  'find': findDB(myDict, params[1]),
                  'del': removeDB(myDict, params[1], params[2]),
                  'clear': clearAll(myDict)}
    inpt = None
    while inpt != "End":
        inpt = input("-->")
        params = inpt.split()
        methodDict[params[0]]

Here is my code, when I try to execute the code I get, "UnboundLocalError: local variable 'params' referenced before assignment"

Is it possible to do what I am trying to do in python?

Answer 1

So, what actually happens at

 methodDict = {'add': addDB(myDict, params[1], params[2]),
              'find': findDB(myDict, params[1]),
              'del': removeDB(myDict, params[1], params[2]),
              'clear': clearAll(myDict)}

is that you execute addDB etc, that is, your methodDict would contain the result of addDB(...params...) if it were to run.

Unfortunately it does not run, as params is not defined when that execution happens.

What you'd want to do is, store a callable in the dictionary and run it... something like

methodDict = {'add': lambda x: addDB(myDict, x[0], x[1])}
# and you execute with
methodDict['add'](params)